For real mil-spec ruggedness, you can't beat one of the newer military
surplus composite plastic(?) gasketed ammo boxes. They are waterproof, and
the one I have looks like you can drive a small car over it.
Mine came from Hunt's Hardware in nearby Miller, MO. But that was a few
years ago, and I doubt that they have any more that weren't made for the
military. Maybe you can find one online.
The non-mil-spec ammo box that housed my tuner at the base of my inverted-L
I got from that same store. Photos at
www.w0btu.com/files/antenna/160m_inv-L. Maybe your local hardware has one.
But it's not rugged enough to drive a car over. :-)
73, Mike
www.w0btu.com